JPH0873695A - High elongation macromolecular network structure - Google Patents

Abstract

PURPOSE: To provide a high-elongation macromolecular network structure which has more than 500% elongation at break (Eb) and is excellent in vibration absorption, vibration damping, cushioning and shock absorption. CONSTITUTION: This network structure is obtained by mixing less than 35-vol.% of a block copolymer which has 5-70wt.% polyethylene content and comprises a polyethylene of more than 50,000 number-average molecular weight and an ethylene-styrene random copolymer with more than 65vol.% of a low-molecular weight material of less than 20,000 number-average molecular weight. The block copolymer forms the skeleton of the three-dimensional network and the continuous spaces in the skeleton are filled with the low-molecular weight material and shows more than 500% tensile elongation at break.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high elongation polymer network structure suitably used as a vibration damping material, a vibration damping material, a shock absorbing material, a shock absorbing material and the like.

[0002]

BACKGROUND OF THE INVENTION As is well known, the phase morphology (morphology) obtained when different substances are mixed depends on the amount ratio of each component, compatibility, mixing conditions and the like. For example, in terms of the amount ratio of each component, in many cases, when the content ratio of both components I and II is about 50:50, both components I and II form a continuous phase. On the other hand, when only the component I is increased, on the other hand, the larger component I tends to be dispersed as a continuous phase and the smaller component II as a discontinuous phase. In particular, when one component I is 70% or more and the other component II is 30% or less, 30% or less of component II
Tends to be a discontinuous phase. This is understandable considering that the maximum filling rate when filling spheres in a cube is 74% (volume fraction).

In fact, the literature ("Polymer Alloy" -Basics and Applications "edited by The Polymer Society of Japan, published by Tokyo Kagaku Dojin, No. 380
The page also says: "A component with a large volume fraction tends to be a sea phase. A component of 75% or more is a sea phase regardless of other conditions, and a component of 25% or less is an island phase regardless of other conditions. In addition, depending on the mixing conditions, 25-75% of the components may be indefinite, whether it is the sea, the island, or the sea or the island. " Of course, the form of the phase greatly depends on the compatibility between the components to be mixed, and the higher the compatibility, the easier the microscopic phase separation is, and the relatively small amount of the component is likely to be the continuous phase. Conversely, when the compatibility is very poor (eg, water-oil system), vigorous stirring causes a considerable microphase separation for a short period of time, but this phase separation is extremely unstable. Yes, the phase shifts to a macroscopic phase separation state with the passage of time.

In any case, it is generally difficult to form a stable three-dimensional continuous phase in the minor component by mixing the minor component of 25% or less and the major component of 75% or more.

By the way, conventionally, a vibration damping material, a vibration damping material, a cushioning material,
Although elastic bodies such as rubber are used for shock absorbers and other applications, conventional elastic materials are generally made of a single substance, and there are few proposals for high-stretch materials composed of different materials. Not done.

The present invention has been made in view of the above circumstances, and is a novel high elongation polymer network composed of a mixture of different substances, which can be used as a vibration damping material, a vibration damping material, a shock absorbing material, a shock absorbing material, or the like. Provide a structure.

[0007]

Means for Solving the Problems and Actions The inventors of the present invention have made earnest studies to achieve the above object, and as a result, have a polyethylene content of 5 to 70% by weight and a number average molecular weight of 5
Polyethylene of more than 30,000 and ethylene / styrene random copolymer 35% by volume or less and number average molecular weight of 20,
The block copolymer forms a three-dimensional network-like skeleton by mixing 65% by volume or more of low molecular weight material of 000 or less with 65% by high speed, and the low molecular weight material fills the internal communication space of the skeleton. You can get the structure,
It was found that this structure has an elongation at tensile break of 500% or more.

That is, for example, a polyurethane foam having an open cell structure impregnated with a low molecular weight material (oil) is
Although structurally similar to the above structure, the elongation at tensile rupture of this is about 100 to 200%, and natural gel bodies such as konjak are structurally similar to the above structure, but their tensile rupture. The time growth is about 100%,
Although it hardly expands, the above structure is a composite of different materials of a polymer material forming a three-dimensional network skeleton and a low molecular material filling the internal communication space, and as described above, Despite having the same kind of three-dimensional network structure as polyurethane foam, it shows a remarkable elongation of 500% or more,
In addition, it has low elasticity and is excellent in various properties such as vibration damping, vibration damping, shock absorbing and shock absorbing properties, and it was found to be useful as a vibration damping material, vibration damping material, shock absorbing material, shock absorbing material, etc. The present invention has been completed.

Therefore, the present invention has a polyethylene content of 5
65% by volume of a low molecular weight material having a number average molecular weight of 50,000 or more and a number average molecular weight of 50,000 or more and a block copolymer of ethylene / styrene random copolymer of 35% by volume or less and a number average molecular weight of 20,000 or less. % Or more, the block copolymer forms a three-dimensional network skeleton, and the low molecular weight material is a structure that fills the internal communication space of the skeleton and its elongation at the time of tensile rupture. Is 500% or more, and a high elongation polymer network structure is provided.

The present invention will be described in more detail below. In the present invention, the polymer material for forming the three-dimensional network skeleton structure of the high elongation polymer network structure comprises polyethylene and an ethylene / styrene random copolymer. A block copolymer is used.

This block copolymer can be obtained by hydrogenating a block copolymer of polybutadiene and a butadiene / styrene random copolymer.

In the present invention, the block copolymer of polyethylene and an ethylene / styrene random copolymer has a polyethylene content of 5 to 70% by weight, preferably 1
0 to 65% by weight, more preferably 20 to 60% by weight is used. If the polyethylene content is too low, the strength of the resulting composite will be reduced, and the composite will flow without retaining its shape. Conversely, if the polyethylene content is too high, the elastic modulus of the resulting composite will be high, and the desired anti-vibration property, Various performances such as vibration damping property, shock absorbing property and shock absorbing property cannot be obtained.

The block copolymer has a number average molecular weight of 5,000 or more, preferably 70,000.
Although the above-mentioned materials are used, a higher molecular weight is preferable for the purpose of increasing the elongation at tensile break of the present invention. The upper limit of the molecular weight is not particularly limited, but is usually 500,000.

On the other hand, the low molecular weight material to be mixed with the above polymer material has a number average molecular weight of 20,000 or less, preferably 10,000 or less, and such low molecular weight material is not particularly limited. However, the following are suitable.

Softening agent: Softening agent for various rubbers or resins such as mineral oils, vegetable oils and synthetic oils. Examples of the mineral oil-based oil include process oils such as aromatic oils, naphthene oils, and paraffin oils. Examples of vegetable oils include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, wood wax, pine oil, olive oil and the like.

Plasticizers: various ester plasticizers such as phthalic acid esters, mixed phthalic acid esters, aliphatic dibasic acid esters, glycol esters, fatty acid esters, phosphoric acid esters, stearic acid esters, epoxy plasticizers, etc. Plasticizers for plastics or phthalate-based, adipate-based, sebacate-based, phosphate-based, polyether-based, polyester-based plasticizers for NBR.

Tackifier: coumarone resin, coumarone-
Various tackifiers such as indene resin, phenol terpene resin, petroleum hydrocarbon, and rosin derivative.

Oligomer: Crown ether, fluorine-containing oligomer, polyisobutylene, xylene resin, chlorinated rubber, polyethylene wax, petroleum resin, rosin ester rubber, polyalkylene glycol diacrylate, liquid rubber (polybutadiene, styrene-butadiene rubber,
Butadiene-acrylonitrile rubber, polychloroprene, etc.), silicon-based oligomers, various oligomers such as poly-α-olefins.

Lubricants: Hydrocarbon lubricants such as paraffin and wax, fatty acid lubricants such as higher fatty acids and oxyfatty acids, fatty acid amide lubricants such as fatty acid amides and alkylenebisfatty acid amides, fatty acid lower alcohol esters, fatty acid polyhydric alcohol esters. , Ester-based lubricants such as fatty acid polyglycol esters, alcohol-based lubricants such as fatty alcohols, polyhydric alcohols, polyglycols and polyglycerols, various lubricants such as metal soaps and mixed lubricants.

In addition, latex, emulsion, liquid crystal, bituminous composition represented by straight asphalt, blown asphalt, clay, natural starch, sugar, silicone oil, phosphazene and the like are also suitable as the low molecular weight organic substance. Further, animal oils such as beef oil, pork oil, horse oil, bird oil or fish oil, dairy products such as honey, fruit juice, chocolate and yogurt, hydrocarbons, halogenated hydrocarbons, alcohols, phenols, ethers. Organic solvents such as acetal-based, ketone-based, fatty acid-based, ester-based, nitrogen compound-based, sulfur compound-based, or various medicinal components, soil modifiers, fertilizers, petroleum, water, aqueous solutions and the like are also used. These components may be used alone or in combination of two or more.

The structure of the present invention forms a three-dimensional network skeleton from the above-mentioned polymer material by mixing the above-mentioned polymer material and the low-molecular material. In this case, the amount of the polymer material used It is preferable to form a three-dimensional reticulated skeleton with as small an amount as possible, and the volume fraction of the polymer material (= volume of polymer material / (volume of polymer material + volume of low molecular weight material) is 35% or less, preferably Is preferably 30% or less, more preferably 25% or less so that a three-dimensional network skeleton can be effectively formed. The lower limit of the volume fraction of the polymer material is 3%, preferably 5
% Is preferred.

The structure of the present invention may further contain the following fillers, if necessary. That is, clay, diatomaceous earth, carbon black, silica, talc, barium sulfate, calcium carbonate, magnesium carbonate, metal oxides,
Mica, graphite, scale-like inorganic filler such as aluminum hydroxide, various metal powder, wood chips, glass powder, ceramic powder, granular or powder-like solid filler such as powder polymer,
Other various natural or artificial short fibers, long fibers (for example,
Straws, hairs, glass fibers, metal fibers, other various polymer fibers, etc.) can be blended. Further, a balun having a hollow inside, for example, a glass balun, a ceramic balun, a polymer organic material balun made of polyvinylidene chloride, or the like may be blended. The blending amount of these fillers is preferably 1,000 or less when the total weight of the high molecular weight material and the low molecular weight material is 100.

To obtain the structure of the present invention, the high molecular weight material and the low molecular weight material are agitated at high speed. In this case, the stirring speed is 300 rpm or more, preferably 500 rpm or more,
It is more preferably 1,000 rpm or more. As a mixer, the shear rate of the rotor is 5 ×.
A high shear mixer having a capacity of 10 ² sec ^-1 or more is most suitable. The mixing time is preferably 2 minutes to 3 hours, and particularly preferably 3 minutes to 2 hours.

The mixer temperature during kneading is basically the melting point of the polymer material used (when the polymer material has a crystal structure) or the glass transition point (when the polymer material has an agglomerated structure). It is preferable to keep the temperature higher. However, when the compatibility between the high molecular weight material and the low molecular weight material used is extremely good, it is possible to carry out the kneading at a temperature below the melting point or the glass transition point.

In the structure of the present invention, the high-molecular material and the low-molecular material are agitated at high speed as described above, whereby the high-molecular material forms a three-dimensional network skeleton, and the low-molecular material communicates with the internal structure of the skeleton. Although it is obtained as a structure that fills the space, in this case, the size of the internal communication space (cell diameter) of the three-dimensional reticulated skeleton body is preferably 80 μm or less, more preferably 50 μm or less. If it is larger than 80 μm, exudation of a low molecular weight material, particularly oil, may occur, or the air loss (heat loss) may increase. Further, the thickness of the skeleton is preferably 8 μm or less, and particularly preferably 5 μm or less. The diameter of the cell and the thickness of the skeleton can be adjusted within a predetermined range by appropriately selecting the stirring conditions and the like.

The structure of the present invention has an elongation at tensile rupture (using a JIS No. 2 test piece, and a tensile speed of 5 at 25 ° C.).
Strain at break E _b ) when pulled at 00 mm / min is 50
It is 0% or more, and more preferably 700% or more.
Further, the weight loss (heat loss) of the low molecular weight material when kept in air at 50 ° C. for 150 hours is preferably 1% or less.

Since the structure of the present invention has a high elongation of _Eb of 500% or more and has a low elasticity and a high damping property, it is used as a vibration-damping / damping / cushioning material such as a sealing material and a packing. , Gaskets, fixing members such as grommets, support members such as mounts, holders and insulators, buffer members such as stoppers, cushions and bumpers. Furthermore, as cushioning absorbents, sports equipment such as clubs, mitts, golf clubs, and tennis rackets, for insoles of shoes, various toys, audio equipment, electronic / electrical equipment, beds, chairs, etc. It is suitable for use as a material for car beds, barber / beauty beds, theater chairs, and vehicle seats subject to vibration. In addition, it is used for medical equipment such as artificial legs, artificial hands, robots, electrode materials for electrocardiogram measurement, electrode materials for low-frequency therapeutic devices, etc., as ultra-low hardness rubber for OA equipment, seismic isolation rubber, anti-vibration rubber, racing tires, etc. Also used for. In addition, it is suitable as a low hardness plastic for various molding materials, and it is possible to control the release of liquid low molecular weight organic substances to the outside. Therefore, the release properties of fragrances, medical agents, functional materials, etc. are used. It is also used for various sustained release materials. Furthermore, since the liquid low molecular weight organic substance can be handled as a solid state, it is also suitable as a functional material such as an electrolytic solution film, a liquid crystal film, an adhesive film, and a paint film.

[0028]

The high elongation polymer network structure of the present invention is E
_{b Since} it has an elongation at break of 500% or more, it has excellent vibration-damping, vibration-damping, shock-absorbing and shock-absorbing properties.

[0029]

EXAMPLES The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Examples and Comparative Examples] Polyethylene obtained by hydrogenating a two-block copolymer of polybutadiene and a butadiene / styrene random copolymer, and having polyethylene content and number average molecular weight shown in Tables 1 to 3 A 2-block copolymer with an ethylene / styrene random copolymer was used as a polymer material, and the low molecular weight materials shown in Tables 1 to 3 were mixed in the ratio shown in the same table, and the mixture was mixed using a high shear mixer. By stirring under the conditions shown in, a polymer network structure having a three-dimensional network skeleton structure was produced.

Next, the elongation at break, loss on heat, cell diameter, and skeleton thickness were measured by the following methods. The results are shown in Table 1.
~ 3. Elongation at break Using a JIS No. 2 test piece, pulling speed 500 at 25 ° C
The strain at break E _b when pulled at mm / min was measured. Loss on Heat The loss on heat was measured when it was held in air at 50 ° C. for 150 hours. Cell diameter and skeleton thickness were calculated from micrographs.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

The examples 1 to 3 and 9 to 12 are effective as the vibration absorbing material, the cushioning material, and the shock absorbing material, and the examples 4 and 5 are the damping material and the shock absorbing material. Is a damping material,
The shock absorbing material of Example 7 is effective as a cushioning material, the shock absorbing material, and the material of Example 8 is effective as a vibration damping material, a cushioning material, and a shock absorbing material.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yuichiro Wakana 3-5-5-763 Ogawa Higashi-cho, Kodaira-shi, Tokyo (72) Miei Fukahori 2-9-7 Sanada-cho, Hachioji-shi, Tokyo

Claims (1)

[Claims] 1. A block copolymer of polyethylene having an ethylene content of 5 to 70% by weight and a number average molecular weight of 50,000 or more and ethylene / styrene random copolymer of 35% by volume or less and a number average molecular weight of 20. A structure in which the block copolymer forms a three-dimensional network skeleton, and the low-molecular material fills the internal communication space of the skeleton, which is obtained by mixing 65% by volume or more of low molecular weight material of 1,000 or less. The body has an elongation at break of 500
% Or more, high elongation polymer network structure.